Galaxy as fundamental calibrator of the extragalactic distance scale. I. The basic scale factors of the galaxy and two kinematic tests of the long and short distance scales
A new version of the oldest approach to estimating the distances of galaxies (direct comparison with our Galaxy) is proposed to relate the extragalactic distance scale to the basic metric, photometric, and kinematic scale factors of the Galaxy. These include the galactocentric distance of the Sun, R/sub sun/, the total magnitude of the Galaxy, M/sup 0//sub T/, and its spheroidal component, M/sup 0//sub I/, the galactic rotation velocity of the local standard of rest, V(R/sub sun/), the central velocity dispersion sigma/sub ..nu../(0) of the spheroidal component, and related parameters. The following ''most probable'' values and their mean errors are adopted from a variety of recent determinations: morphological type of galaxy, SABX(rXs)bc(T = 4 +- 0.5), R/sub sun/ = 8.5 +- 0.5 kpc, M/sup 0//sub T/(B) = -20.2 +- 0.15, (B-V)/sup 0//sub T/ = 0.53 +- 0.04, M/sup 0//sub I/(B) = -18.2 +- 0.3, (B-V)/sup 0//sub I/ = 0.65 +- 0.05, V(R/sub sun/) = 220 +- 15 km s/sup -1/, sigma/sub ..nu../(0) = 130 +- 7 km s/sup -1/. 1. The zero points of the Tully-Fisher (T-F) relations, -M/sup 0//sub T/(B) = a(B)+5(log V/sub M/ -2.2), in the B/sub T/ system, and -M/sup c/(H) = a(H)+10(log W/sub 20/-2.5), in the H/sub -0.5/ system, are determined in terms of the galactocentric distance of the Sun R/sub sun/, and the galactic rotation velocity of the local standard of rest, V(R/sub sun/)equivalentV/sub 0/roughly-equalV/sub M/, or the corresponding line width W/sub 20/. The galactic zero point a(B) agrees within 0.1 mag with that (19.4 +- 0.15) previously derived on the short scale from 11 nearby calibrating galaxies.
- Research Organization:
- Department of Astronomy and McDonald Observatory, University of Texas, and Mount Stromlo and Siding Spring Observatories, Australian National University
- OSTI ID:
- 5721309
- Journal Information:
- Astrophys. J.; (United States), Vol. 268:2
- Country of Publication:
- United States
- Language:
- English
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